The present invention relates to a multiple-piece solid golf ball.
Although there are many factors that affect the carry of a golf ball, among these, the three factors of initial ball velocity, striking angle, and amount of spin are referred to as the three elements of ball carry, and are considered to be very important. Of these, the initial velocity of the ball is restricted by regulations.
Golf balls are developed in accordance with the above-noted regulations, many of them being developed for professional golfers and advanced amateurs with a high head speed, and when struck by a player having a low head speed, the initial velocity of the ball is much lower than the limited imposed by the regulations, and it is sometimes not possible to achieve a satisfactory carry.
In Japanese Patent Application Publication 2000-350795, in order to achieve an initial ball velocity that is close to the case in which the ball is struck at a relatively high head speed of approximately 50 m/s even if the golf ball is struck at a relatively low head speed of approximately 40 m/s, there is a description of a solid golf ball with a solid core with a multilayer construction that includes an innermost core and at least one layer covering the innermost core and a cover that covers the solid core, wherein the innermost core exhibits a rebound of less than 95 cm when free falling from a height of 120 cm, and also wherein the diameter of the above-noted innermost core is 18 mm or smaller.
Also, in Japanese Patent Application Publication 7-155403, there is a description, for the purpose of providing a golf ball having high repulsion performance, of the use as a material to form the solid core of the golf ball of a rubber composition using as the main component a diene rubber having a loss tangent (tan δ) of 0.01 or greater and 0.2 or lower. Also, in Japanese Patent Application Publication 2000-51394, for the purpose of providing a golf ball having a soft feel on impact but a small reduction in repulsion performance, there is a description of the use of a material having a JIS-A hardness of 70 or less and also a loss tangent (tan δ) of 0.03 or lower.